| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem which arises in a breakdown voltage when using a miniaturized semiconductor element for a laser diode driving device of a high operating voltage such as a short wavelength laser, since the breakdown voltage tends to lower while high frequency characteristics are improved by the miniaturization of the semiconductor element. SOLUTION: The laser diode driving device includes: a variable current source (1) capable of adjusting a current to be made to flow to a laser diode; a current driving circuit (2) capable of amplifying the output current of the variable current source; operation detection means (6, 7, 8) for detecting the operating state of the laser diode (5); a protective circuit (3) operated so as to secure the breakdown voltage of the current driving circuit (2) when not making the laser diode (5) perform a light emitting operation; and a protective voltage generation circuit (4) for generating a voltage capable of securing the breakdown voltage of the current driving circuit (2) and the protective circuit (3) and transmitting it to the protective circuit (3). COPYRIGHT: (C)2011,JPO&INPIT
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